Advances in the technology and supportive care associated with bone marrow and stem cell transplantation (BMT) have led to improved medical outcomes for children with cancer and other catastrophic illnesses. However, the BMT procedure remains a prolonged, physically and emotionally demanding experience for patients and families. Our current research has demonstrated that patients experience a high level of somatic distress and associated mood disturbance during the acute phase of BMT, and further, that parental caregivers also experience a high level of emotional distress during the same procedure. Although this distress is relatively transient, research on long-term psychosocial outcomes in BMT suggests that it may be associated with later disturbances in the social functioning, self-esteem, and general emotional well-being of survivors, as well as with an increased risk of post-traumatic stress symptoms in survivors and their parents. Novel interventions to reduce the stresses of BMT are needed, but few empirical studies of psychosocial interventions during BMT have been reported, and those have involved only adult patients. The results of our pilot study testing a multi-component, health promotion intervention for patients during their BMT hospitalization indicated that two components; massage and humor therapy, were rated as significantly more helpful than the others. These findings have guided the design of this proposed randomized intervention trial. The overall aim of the proposed project is to evaluate the impact of a health promotion intervention for childrenundergoing bone marrow or stem cell transplant (BMT). The intervention is complementary in nature, designed to increase the experience of positive affect and reduce somatic distress and mood disturbance, that is, to improve overall child well being. The study will utilize a positive psychology model, exploring the hypothesis that unproved outcomes will be mediated by the increased experience of positive affect states brought about by the intervention. The primary focus is on a child-targeted intervention that includes massage therapy and humor therapy. The study will also assess whether the addition of a similar parent-targeted intervention involving massage therapy and relaxation training will provide significant benefits beyond those provided by the child-targeted intervention alone. Both child and parent interventions will include a significant education component, guided by our model of positive psychology. The study will utilize a 3-group design, with participants randomized to receive: 1) a child-targeted intervention; 2) a child targeted intervention plus a parent-targeted intervention; 3) standard care. Primary outcomes include child positive affect, somatic distress and mood disturbance, as well as measures of parental positive affect and distress. Additional objectives of the study include examining the impact of the intervention on short-term medical outcomes, as well as measures of child adjustment and parent and child post-traumatic stress symptoms (PTSS) at 6 months post-BMT. Finally, analyses will explore hypotheses specific to the positive psychology model, testing the role of positive affect and dispositional optimism as mediators and moderators of the intervention on child and parent well being.